1. Field of the Invention
The present invention relates to a spin dryer, more particularly a spin dryer for drying substrates adapted for producing semiconductor devices.
2. Description of the Prior Art
In semiconductor device production processes, particularly wafer processes and also photomask processes, a substrate is treated by a succession of reagent solutions. After each treatment, the substrate has to be washed with pure water or alcohol and then dried. For drying, the substrate is mounted on a spin dryer and subjected to high speed rotation, e.g., 3000 to 5000 rpm, by means of an electric motor. The resultant centrifugal force quickly drives the washing liquid off the substrate. This quick drying is necessary in order to avoid oxidation or dust contamination of the substrate.
In the prior art spin dryers, however, the upper surface of the substrate is still left exposed to the ambient atmosphere. Thus, during rotation, even if only of a short time period, the substrate is contacted by the atmosphere and minute dust deposits thereon, contaminating the substrate and reducing the quality of the resultant semiconductor devices.